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Subjects with intensively-treated type 1 diabetes and glycated hemoglobin (HbA1c) 7.0%-10.0% in 3 age groups (>25, 15-24, 8-14) will be randomized to a continuous glucose monitoring (CGM) group or control group. The primary outcome is change in HbA1c after 26 weeks. A parallel randomized trial is being conducted for a second cohort with HbA1c <7.0% that will follow an identical protocol to that of the first cohort with HbA1c >=7.0%.

The >=7.0% trial was specifically designed and statistically powered to compare separately the impact of continuous versus standard intensive glucose monitoring in the three age groups. Both trials used standardized treatment algorithms and equivalent frequent contacts with subjects in both the CGM and control group.

After completion of the 26-week trial, the CGM group continues to use CGM for another 26 weeks to evaluate whether any beneficial effect seen in the first 6 months is sustained with longer-term use and less intensive contact and the control group initiates CGM use with less intensive contact after the first month than was provided at initiation of CGM use in the CGM group in the randomized trial.

Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Data regarding continuous glucose monitoring were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Glucose variability was assessed by computing the absolute rate of change.

Change in Glycated Hemoglobin (HbA1c) From Baseline to 26 Weeks in the Continuous Glucose Monitoring (CGM) and Control Groups (for the Cohort With Baseline HbA1c <7.0% Cohort) [ Time Frame: Baseline and 26 weeks ]

The secondary outcome was the change in glycated hemoglobin (HbA1c) from baseline to 26 weeks in the Continuous Glucose Monitoring (CGM) and Control groups (for the cohort with baseline HbA1c <7.0% cohort), as determined by a central laboratory.

Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Data regarding CGM were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Data regarding continuous glucose monitoring were obtained after completion of the 26-week visit with the use of an unblinded device in the RT-CGM group and a blinded device in the Control group. Measure consists of minutes/day in range.

Glucose variability was assessed by computing the absolute rate of change.

Quality of Life [ Time Frame: 26 weeks ]

Hypoglycemia Fear Survey Total Score Average score of all items giving equal weight to each item. Scale 0-100 with higher score denoting more fear or more likely to avoid low blood glucose.

Cost-effectiveness of CGM. [ Time Frame: 26 weeks ]

Estimated total costs divided by estimated Quality-Adjusted Life Weeks (QALW) calculated per group

QALW [ Time Frame: 26 weeks ]

Quality Adjusted Life Weeks: We collected experienced utility data by eliciting time tradeoff (TTO) utilities for overall experience. Patients were asked to consider their current state of health in comparison to life in perfect health. Experienced utilities were elicited at baseline, 13 weeks, and 26 weeks. For children aged <18 years, parents served as surrogates. The total quality-adjusted life weeks (QALWs) were calculated as the area under the quality-of-life time trends under each arm.

Total Costs: Direct and Indirect Costs [ Time Frame: 26 weeks ]

Investigators reported time spent with patients on CGM training and diabetes management excluding research time. Adult patients (or caregivers of children) self-reported health service utilization including routine office visits, after-hours clinic visits, emergency room visits, 911 calls, and hospitalizations. The daily cost of CGM technology was calculated based on FDA recommended frequency of sensor replacement and the expected frequency of receiver and transmitter replacement. The costs of the three devices used during the trial were averaged to arrive at a daily cost of CGM of $13.85. This daily cost was multiplied by the reported weekly use of CGM to arrive at an overall cost of CGM technology. Indirect costs: self-reported number of hours devoted to diabetes care per day, number of days missed from work or school due to diabetes, and number of days of work underperformance. Unit costs available at: http://care.diabetesjournals.org/cgi/content/full/dc09-2042/DC1 (Table 1).

Patients in the control group were given blood glucose meters and test strips and asked to perform home blood glucose monitoring at least four times daily.

Active Comparator: Continuous Glucose Monitoring (CGM)

Patients in the CGM group were instructed to use the CGM device on a daily basis and to verify the accuracy of the glucose measurement with a home blood glucose meter (provided by the study) before making management decisions (as per the regulatory labeling of the devices).

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Ages Eligible for Study:

8 Years and older (Child, Adult, Senior)

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Clinical diagnosis of type 1 diabetes and using daily insulin therapy for at least one year

The diagnosis of type 1 diabetes is based on the investigator's judgment; C peptide level and antibody determinations are not needed.

Age >8 years

Glycated hemoglobin(HbA1c) 7.0%-10.0% for the primary cohort and <7.0% for the secondary cohort

The DCA2000 or comparable point of care device will be used to assess eligibility.

Insulin regimen involves either use of an insulin pump or multiple daily injections of insulin (at least 3 shots per day) and has been stable for the last two months, with no plans to switch the modality of insulin administration during the next 6 months (e.g., injection user switching to a pump, pump user switching to injections, or the addition of Lantus (Glargine) insulin)

Subjects using premixed fixed doses of insulin at the time of enrollment will not be eligible

Subject (and parent/guardian for children) understands the study protocol and agrees to comply with it

Subjects >9 years old and primary care giver (i.e., parent or guardian if subject is a minor) comprehend written English or Spanish

This requirement is due to the fact that the questionnaires to be used as outcome measures do not have validated versions in other languages.

Spanish-speaking subjects will be enrolled only if a RT-CGM device that functions in Spanish and has a User Guide in Spanish is available.

No expectation that subject will be moving out of the area of the clinical center during the next year, unless the move will be to an area served by another study center.

Informed Consent Form signed by the subject (or parent/guardian if subject is a minor, with subject signing the Child Assent Form)

Exclusion Criteria:

The presence of a significant medical disorder or use of a medication such as oral/inhaled glucocorticoids that in the judgment of the investigator will affect the wearing of the sensors or the completion of any aspect of the protocol.

The presence of any of the following diseases:

Asthma if treated with systemic or inhaled corticosteroids in the last 6 months

Cystic fibrosis

Adequately treated thyroid disease and celiac disease do not exclude subjects from enrollment

Inpatient psychiatric treatment in the past 6 months (if the subject is a minor, for either the subject or the subject's primary care giver).

For females, pregnant or intending to become pregnant during the next year Pregnancy is an exclusion because of uncertainty about the lag between interstitial fluid glucose and blood glucose during pregnancy, which might affect the accuracy of the sensor. Subjects who become pregnant during the study will be discontinued from the study.

Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00406133